


All the King's Horses

by TFWBT



Category: Supernatural
Genre: Anal Sex, Angst, Dark, Demon Dean Winchester, Demon!Dean, Dubious Consent, Hurt Sam Winchester, Kinktober, Kinktober 2017, M/M, Mark of Cain, Past Rape/Non-con, Season/Series 10, Sibling Incest
Language: English
Status: Completed
Published: 2017-10-07
Updated: 2017-10-07
Packaged: 2019-01-10 00:54:36
Rating: Explicit
Warnings: Rape/Non-Con
Chapters: 2
Words: 8,772
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12287823
Author URL: https://archiveofourown.org/users/TFWBT/pseuds/TFWBT
Summary: Sam and Castiel try to honor Dean's wishes and help Dean fight the Mark instead of using the Book of the Damned to remove it. The cost is high, especially for Sam; however, there's nothing he won't do for his big brother.





	1. All the King's Horses (Cas Version)

**Author's Note:**

> Written for Kinktober. This is set in a longer version of season 10. Sam and Dean are the only characters who have sex in this story, although there are references to past non-con that happened in the cage with Lucifer. Not a happy story. Dean isn't fully Dean when under the Mark.
> 
> Disclaimer: I do not own Supernatural and never will. 
> 
> Since Castiel's name has two spellings, the first chapter has Cas and the second chapter is the exact same sorry with Cass so everyone can read their favorite spelling!

The hunt is a bad idea. They'd given Dean the full cure barely three months before, but what Sam thinks will be a milk run turns into a nest of vampires. Sam should’ve been more cautious. Dean gets worse when Sam gets hurt. When the vampire slams Sam into the wall, his fangs inches from Sam's neck, Sam isn't afraid of the vampire, but of what Dean will do.

After Dean slaughters the vampires, Sam secretly tests him with holy water. He passes, and Sam sighs with relief. It isn't until later, when they're back at the bunker and Dean stomps around and yells at Sam for forgetting to restock the beer, that Sam realizes the Mark of Cain has taken control again.

Dean stalks to his room and Cas and Sam meet in the library.

They discuss drugging Dean again, but the Mark makes him unresponsive to normal dosages. Besides, it they do it too often, Dean will get suspicious.

“Would you like me to try?” asks Cas, his voice soft as he looks at Sam with those piercing blue eyes. “I don't mind.”

“No- no, Cas. I got this,” says Sam. Six months ago, he would've been shocked at how easily Cas offers his body- casual as if he's offering to make Dean a sandwich. But they're getting desperate. “He's my responsibility.” _My fault. He sold his soul for me. I left him in purgatory. I didn't shut down the gates of hell. I drove him away instead of working things out. I..._

“This isn't your fault,” says Cas. Again. Sam's lost track of how many times he's said it. He must hear it once a week.

“I'll put him to sleep,” Sam says. “I've got the blood ready. You work on resting, so you'll be ready if I can't get him down, or for the next time he goes full demon.” They both know it's no longer 'if’, but ‘when’. “Besides, I need you at full strength for afterwards anyway.”

Cas nods and once again, Sam is glad that Cas never looks at Sam with pity **.** Never treats Sam as if he's done anything shameful. As if what Sam does is a normal thing for brothers to do.

Sam goes to his room to prepare. He changes his clothes, makes confession, and tucks a syringe of consecrated blood into the pocket of his sweatpants. He stops by the kitchen to make a sandwich, although he doubts it will be eaten.

As he walks to Dean's room, he wonders if he isn't overreacting. It had been a long hunt with little sleep and it was just one comment. Maybe it was just Dean being Dean. Then he sees Dean inside his room, pacing. He's moving around restlessly as if he has an itch he just can't scratch. Sam sees an empty bottle of rum, even though he and Cas did an alcohol sweep before they left.

Cas is waiting just out of view of Dean's room. Sam nods at him in reassurance.

“I'll be in my room,” says Cas and he reaches out and gives Sam's hand a squeeze before walking past.

Sam closes the door behind him and hears Cas lock it from the outside.

Sam knows Cas will wait for his prayer, just in case. Sam has only needed him twice. Twice when they hadn't realized Dean had been killed and had gone full demon. It's harder now that he comes back within minutes of death. Sam knows black eyes are a possibility tonight. He sets the sandwich on Dean's desk and smiles. “Wanna watch something? I saw some new shows on Netflix.”

Dean scowls at him. He seems so much bigger when the Mark has control. He seems to loom over Sam despite the fact that he's shorter. He looks at Sam and Sam doesn't see much of the brother who was there yesterday.

“Sure,” he grunts but he doesn't stop pacing. Doesn't even look at the sandwich.

If Sam's lucky, Dean will settle down and binge watch a show with him until he passes out from all the drinking.

If Sam's not, Sam will handle it. He always has.

Sam edges over and turns on the TV, moving slowly and deliberately so Dean can see he isn't a threat. He sits in the chair by the bed and offers Dean the remote.

Dean selects a show without looking at the TV. He must've been suppressing the Mark longer than they'd realized, because his fingers keep stretching out into empty space; as if searching for the jawbone. Sam recognizes the signs. It won't be easy tonight.

“You almost died,” says Dean. He doesn't look at Sam. His fingers are flexing. Open and closed. Open and closed.

“I was fine,” says Sam, although he probably would've been dead if Dean hadn't had the Mark.

Dean moves, and one minute Sam is in the chair- the next he’s on his feet, pressed into the wall, Dean gripping his arms so tightly he'll have bruises the next morning.

“It's okay,” says Sam.

“I can't lose you.” There's so much grief and fear amid the anger in his eyes that it makes this easier. Sam can see Dean, the real Dean, through the Mark.

“I'm here,” says Sam. “I'm not gonna leave you.”

Dean pushes against him and kisses him hard, his mouth working possessively over Sam’s mouth and neck. He always smells like Dean - the Mark can't change that. Sam breathes in that mix of the Impala, smoke-stained flannel and denim, and the aftershave Dean's worn since he started wearing it at fifteen. If Sam closes his eyes, he can imagine he's with the real Dean, even with the hands bruising his arms.

Sam soothes him as best he can with his arms still pinned against the wall. “I'm here. I'm here.” He can't help but notice that Dean goes after him quicker each time it happens. At first, Sam gave in and went with it because it was the best way to calm Dean down and get him to sleep. Hard as it was, it's now become as normal as cleaning out and sewing up a bullet wound. He stitches Dean back together no matter how he falls apart.

Finally, Dean releases Sam's arms and Sam can move again. But Dean's already pawing at Sam's clothes. Sam has learned to wear things that can easily be pulled off. The last thing he wants is to make him angry. Dean yanks down Sam's sweatpants and rips off his t-shirt. His hands and mouth seem to be everywhere at once as he presses Sam into the wall again. He touches Sam as if he's drowning and Sam can give him oxygen.

Sam kisses him back, stroking him lovingly, trying to tell him with his body what he knows Dean can't fully hear with his words. “It's okay. I'm here.”

Dean throws him against the bed. Sam scoots more fully on it, lies on his back, and spreads his legs. Usually it takes Dean longer to get to this point.

Dean is still fully dressed as he moves on the bed, his eyes wild and hungry. Reaching between Sam's legs, he stills when he touches the plug Sam put in himself as part of his preparation. When the Mark has full control, Dean doesn't usually use lube or go slowly. Sam normally works it out before they get to this point. He didn't have the chance this time.

One second, Dean is staring at the plug, and the next Dean's hands are closing on Sam's throat. “You whore. Who’re you fucking?”

“No one else,” Sam gasps out. “I swear.”

“Don't lie to me.” Dean's eyes are fire.

“No one else.” Sam wonders if he needs to call Cas.

Just when he's about to, Dean releases Sam's neck. He tears off his shirt and strips himself of his jeans, his cock straining against his boxers. Sam has seen enough of Dean's erections to know that he probably won't get any more foreplay, so he rolls over onto his stomach and gets into a comfortable position.

Moving between Sam's legs, Dean grips the plug and rips it out. The plug is thick, and Sam's used nearly half the bottle of lube, but Dean's cock is huge and it hurts. At least he didn't tear this time. At least he's in the bunker with Dean, instead of in the cage with Lucifer.

Dean steadies his hands on Sam's shoulders, pushing him into the bed. He sets a punishing pace, pulling his cock almost all the way out before slamming it back in.

It's happened so often Sam knows how to give into it. He used to tense, making it hurt worse, but now he knows to calm and relax his body, accepting instead of fighting against the invasion. At least with Dean, he can think of childhood memories to distract himself. He sees memories of Dean taking care of him - wiping away tears, cooking mac and cheese, setting bones and saving his ass. Dean's built his life around taking care of Sam. The least Sam can do is return the favor.

The initial burning subsides, and Sam shifts his hips until Dean's hitting him just right. He doesn't like to think about how quickly he found pleasure in this. He used to think that after what Lucifer did, penetration would always be associated with pain and humiliation. He doesn't like to think about how the difference is Dean, his brother who basically raised him. He's not interested in other men. He’s only wanted to date or sleep with women since he got out of the cage, and when he watches porn, it's always straight. But he'll come from Dean's cock up his ass.

Dean is growling as he snaps his hips. The more the Mark has control, the less he speaks.

Sam strokes Dean’s fingers. “I'm not gonna leave you,” he promises. Dean has him pressed into the bed so hard he can barely breathe.

It normally calms Dean, but this time Dean bends down and bites Sam’s shoulder. Sam grins. Usually he has to work to get Dean to drink. “Harder,” he grunts and Dean obeys, sinking his teeth in until Sam can feel his skin break.

Sam doesn't know why it works. If anything should desecrate blood after a confession, fucking your brother should be towards the top of the list. For some reason though, it works. As Dean laps at the blood, his thrusts ease, no longer brutal.

“Drink,” says Sam. “Drink as much as you want.” Even though Dean isn't a demon now, it's still the best way to calm him down. Sam doesn't like to think about what that means for his brother. Or why Dean normally refuses the blood. This would all be much easier if he would just drink it on a regular basis.

Dean lifts his hands from Sam's shoulders, and snakes one arm under Sam, holding him tightly against his chest as he rolls his hips. Sam grabs his hand, his fingers threading through Dean's as he shifts his hips back to meet Dean's thrusts, his cock hard against the sheets.

“That's good,” says Sam. He knows Dean likes it when he talks, although he never quite knows what to say. “That’s good.”

“I can't lose you,” Dean says again.

It startles Sam. Dean normally never talks when he's like this. Or at least never says anything Sam would like to hear.

“I'm here. I'm not going anywhere.” Sam tries to shift away, and is surprised when Dean lets him, his cock pulling out of Sam's ass. Sam flips onto his back. Dean is looking at him with eyes more human than demon. Sam has done this often enough that he knows one more good hit of blood is all Dean needs to fully return to him.

For once, Dean isn't pushing his way in, so Sam reaches down between his legs and guides Dean's cock back inside him. He likes the feel of it spreading him, filling him, rubbing against his prostate, and making his cock spit precum on his stomach. Yet again, he wonders what the real Dean would think if he knew. Probably nothing good; so Sam never says anything, just takes the pleasure he can get in moments like this.

Sam threads his fingers through Dean's and places their clasped hands by his shoulders. He rolls his hips and that's the only encouragement Dean needs to start fucking him again. He's moving slower now. Sam prefers it hard and fast, but Dean is calmer now, and this isn't about what Sam wants, but what Dean needs.

“Yeah, Dean,” Sam moans. “Keep going.”

Dean is staring at him, and the expression on his face is almost awe. Sam’s never had to question if Dean loves him. Dean's always loved him. For Dean, it's the same as breathing. Even at Sam's worst, Dean still loved him. Sam started the apocalypse against Dean's warnings, and Dean still loved him. Maybe that's part of the problem. Sam always knew that no matter what he did, Dean would love him. He took it for granted. The sun rises, the sun sets, and Dean loves him. Loves him enough to do anything for him. Dean went to hell for him. Offering his body is the least Sam can do.

“You wanna bite me again?”

Dean frowns slightly and Sam realizes he's losing him. He quickly adds, “Harder. Fuck me harder.”

Dean obeys, snapping his hips and hitting Sam just the way he wants. Sam relishes it. He'll try again with the blood later. It's a bit of a problem - the more human Dean is, the less he wants to hurt Sam, so the harder it is to get him to drink Sam's blood.

It's almost perfect at times like these. Dean isn't fully Dean, but he's enough of him that Sam thinks this is bearable. That he could do this for the rest of his life, or until they find a cure that didn't involve the Book of the Damned.

Dean bends down for kiss, and they've done this often enough that Sam knows he's close. He eagerly kisses him back, squeezing around the cock in his ass to push him along. Dean shakes as he comes, his cock pulsing inside Sam as he empties himself.

Usually Sam finishes himself off if he doesn't come from Dean fucking him. But this time Dean slides down his body and licks at his cock.

Sam can't believe it. He freezes, watching Dean with heavy anticipation.

Dean sucks Sam's cock into his mouth. He doesn't take it all, his fingers curling around the base. It's clear from how clumsy the whole thing is that he's never done this before. It's not the best blow job Sam's ever gotten, but it's the one he most appreciates.

Sam was already close from Dean's cock. It isn't long before he tries to push Dean off, warning, “I'm gonna- I'm gonna-”

Dean plants himself firmly. Release flows through Sam, igniting him. He comes down Dean's throat with a soft cry. Feeling warm and lazy, he relaxes against the bed as he smiles at his brother.

Dean lets go of Sam's softening cock, and crawls up the bed to collapse beside Sam, burying his face in the pillow. Sam rubs Dean’s back soothingly. He’s done this often enough that he knows exactly what to do. He hums _Hey Jude_ as he gently massages the tension out of the tight muscles of Dean’s back. He waits until Dean’s breathing is even and heavy before he pulls out the syringe.

He mutters the spell Cas found, and carefully presses the needle into the patch of numb skin on Dean's buttock. It takes a few minutes for the blood to seep into Dean's blood stream, so Sam keeps humming as he massages the flesh. In fifteen minutes, he'll summon Cas.

Dean's phone rings. The noise seems like an air raid siren in the once quiet room. Sam scrambles for the phone, cursing himself for not thinking of turning it off. It's never happened before. He finds the phone and turns it off with trembling fingers. He looks back at the bed. It's too late. Dean's awake. He's staring at Sam.

Sam doesn't know if the second dose has hit or not until the blood drains from Dean's face.

“Dean,” says Sam, moving towards him.

Dean practically teleports. He's on the bed, and then he's pressed against the far wall, his face white and his eyes wide.

“Sam, I- I-” Dean says. Then he vomits.

Sam frowns. Hopefully enough blood got into Dean's system. It's impossible to get him to drink when he's this human.

Dean wipes his mouth with the back of his hand and rasps out, “I raped you.”

 _Not this time_ , thinks Sam. He doesn't say it; he knows it would only wound. He says “It's okay,” keeping his voice soft, the same as with Dean under the Mark.

“It's not! I-”

“It's okay. I chose it,” Sam assures him.

“I'm a monster.” Dean's eyes move to the weapons on the wall.

“No.” Sam moves off the bed, and reaches out for him, but Dean edges away. “It wasn't you. It was the Mark.”

Dean’s eyes are filled such horror, Sam can't help but worry that some of it is directed at him for going along with this. Sam doesn't even know how to explain it. He can't just say, “You can fuck me if you want.” Dean would probably just look at him with the same horror as is on his face now. Sam doesn't even know if that's what he really wants. It's impossible to separate his own desires from his need to give Dean anything he wants. Instead, he says, “You've sacrificed everything for me. I owe you everything. Anything. Dean, you've given me your _life_. Why wouldn't I give you my body? Why wouldn't I do everything I can to help you with this?”

Dean isn't listening. He never listens in these moments. Sam's been through enough to know. “I hurt you,” he says more to himself than Sam. “I nearly strangled you.”

“You didn't.”

“I wanted to.” Without looking at Sam, Dean grabs clothes and pulls them on.

“Wait, Dean, please.” Sam tries to move towards him but Dean flinches away. “I can fix this. You just gotta-” _Go to sleep_. He doesn't know how to say it in a way that won't make Dean suspicious. “Give me some time.”

“No. You don't know.” Dean draws a shaky breath and runs his fingers through his hair. He's talking to the door. “I- I _wanted_ to hurt you. I _liked_ biting you.”

Sam hides his smile. It's a good sign. Maybe it means this is working better than they'd realized. “The Mark wanted to - not you.”

Dean moves for the door. Sam sighs.

Dean doesn't realize the door is locked at first. He stares at it, puzzled, when it won't open. He tries again. And again. “Why is it locked, Sam?” His voice is a growl. Sam realizes Dean can't look in his eyes, or at any part of his body, really. He's talking to the wall behind Sam.

 _Because you're going to try to throw yourself in the Empty_. He doesn't say it. Doesn't want to give Dean any encouragement. It happens every time Dean remembers what he did to Sam while under the control of the Mark. “I can help you,” Sam says instead. “But you gotta let me.” He reaches out in prayer, _Cas, he woke up. I'm going to need you after all._

“God, Sam. Why the fuck are you so calm? How can you-” He presses a trembling hand against his forehead, as if the memories are physically painful.

 _-Enjoy being fucked by your brother?_ Sam doesn't know. “I told you,” he says instead. “You're my big brother. There's nothing I wouldn't do for you. _Nothing_.”

It's the wrong thing to say. Dean retches again, although this time nothing comes out.

It hurts more than Dean choking him. It hurts more than Dean raping him. Once again, he's a freak. He's impure. He's fucked in the head.

The door opens, and Cas slips inside.

Dean looks at him and then, for the first time, directly at Sam. The guilt, shame, and horror so naked on his face breaks Sam in a way Lucifer never could. Cas touches Dean's forehead and Dean collapses to the floor. Sam wants nothing more than to drink himself to sleep. But he helps Cas put Dean on the bed and watches as Cas removes Dean's memory of what just happened. Dean will never remember Sam even entering the room.

“Maybe we should consider removing the Mark,” says Cas after the spell is done. He's panting, sweat dripping off his face. The memory removal process drains him. It will take Cas days to recover. At least he has his grace back so that he _can_ recover, although each memory removal seems to take more out of him. “We can't keep doing this to him.”

He doesn't add _to us_ , even though they both know it's killing them. They both used to try to talk the other out of it, but neither would budge, both willing to give their lives for Dean.

“I know,” says Sam as he tucks Dean into bed. With Dean safely taken care of, he goes to Cas. Sam helps him to trembling feet and guides him back to his room. Cas can barely walk this time. He doesn't complain at all, but he's the most visibly damaged of the three of them.

Next time, Sam will try to handle it on his own. He grimaces at the realization that he's certain there will be another time with a wide awake Dean looking at him like- like-

He can't think about it. If he thinks about it, the darkness inside his heart will eat him alive.

As Sam settles Cas on the bed, Cas grabs his hand, his blue eyes meeting Sam's without pity or disgust- only love. “I know you want to honor Dean's request to stay away from the Book of the Damned but _Sam_ , please - he wouldn't want this for you.”

Sam's got a lump in his throat so thick he can hardly breathe or speak. “I swore I'd respect his choice on this. I don't want to use that book. I know he doesn't want us to use that book. But what am I supposed to do, Cas? Let him throw himself in the Empty? Leave him alone for eternity with all that hate and pain? I know that's what he'll want me to do, because he'd rather get hurt than hurt me. But I can't do that to him. I _can't_. He doesn't deserve that.”

“I know,” says Cas. Cas has offered to go to the Empty himself. But since angels don't have souls, they don't know if he can. After all, why bother with the cage if Lucifer could be thrown into the Empty? There's no way they want to risk leaving Dean there alone.

Sam wants to hate Dean for being so fucking selfless. For loving Sam more than he loves himself. He wishes Dean would let him come with him to the Empty, even though he knows what it would mean for him. He wishes that he could take the Mark, make Dean forget him, and go to the Empty himself. But he can't carve out himself without carving out Dean. He takes a deep breath. “Just let me think about it.”

“It's your choice, Sam,” says Cas. “Whatever you decide.”

Once again, Sam's glad none of this fazes Cas. “If I do decide to use the book…” He hesitates. He's asking a lot and Cas has already done so much; soaked up so much pain for him, and never breathed a word to anyone about what Lucifer did to him. He trusts Cas. “Do you think you could… take my memories of Dean and me... Of everything he did when he...” He swallows and looks at Cas, afraid to ask too much. But Cas is looking at him like he knows exactly what Sam's asking and has already said yes. “If it's too much-”

“I will,” promises Cas. “I may not have the strength to remove all of these memories at once, but I'll make sure you don't remember this part of it.”

“Thank you. For everything.” Sam squeezes his hand. “Now get some sleep.”

Sam heads back to Dean's room. He turns off the TV and sets the room up as if he was never in it that night.

The next morning, Dean saunters into the kitchen, where Sam's mixing eggs. “Whatcha cooking?” Dean says as he brushes past. He's put on fresh aftershave, and Sam imagines Dean's body pressed hard against his.

“Omelettes,” says Sam, his mouth dry. “Want me to add bacon to yours?”

“Yeah, sure.” Dean opens the fridge, smells the milk, and puts it back with a disgusted look on his face. “What happened last night? I remember coming back from the hunt and going to my room, and that’s it.”

“You must've drank too much,” says Sam. He can't look at Dean without picturing Dean's mouth on his cock.

“Yeah… I don't feel hungover though.” He's rooting through the pantry. Sam knows he's looking for carbs. Dean always likes carbs in the morning, but their pantry is picked bare. They need to go to the store.

“Dean, you know I'd do anything for you, right?”

Dean's back goes stiff. He slowly turns. “Is this about the Book of the Damned? I told you to leave it alone.”

“I know, but-”

“That kinda magic always comes with a price.” He's getting visibly angry now. With the Mark, the anger is always there, simmering under the surface. “I'm not the one who's gonna pay it. You are, Sam. I'm not letting you get hurt because of me.”

 _It's too late_ , Sam thinks _. It's too late._ He says, “Yeah, I guess you're right.”

Satisfied, Dean turns back to the pantry.

“You know,” says Sam, “I think I found a case. So get this...”


	2. All the King's Horses (Cas Version)

**Summary for the Chapter:**

> Same exact story, just with Castiel's nickname spelled Cass for those who prefer that spelling.

The hunt is a bad idea. They'd given Dean the full cure barely three months before, but what Sam thinks will be a milk run turns into a nest of vampires. Sam should’ve been more cautious. Dean gets worse when Sam gets hurt. When the vampire slams Sam into the wall, his fangs inches from Sam's neck, Sam isn't afraid of the vampire, but of what Dean will do.

After Dean slaughters the vampires, Sam secretly tests him with holy water. He passes, and Sam sighs with relief. It isn't until later, when they're back at the bunker and Dean stomps around and yells at Sam for forgetting to restock the beer, that Sam realizes the Mark of Cain has taken control again.

Dean stalks to his room and Cass and Sam meet in the library.

They discuss drugging Dean again, but the Mark makes him unresponsive to normal dosages. Besides, it they do it too often, Dean will get suspicious.

“Would you like me to try?” asks Cass, his voice soft as he looks at Sam with those piercing blue eyes. “I don't mind.”

“No- no, Cass. I got this,” says Sam. Six months ago, he would've been shocked at how easily Cass offers his body- casual as if he's offering to make Dean a sandwich. But they're getting desperate. “He's my responsibility.” _My fault. He sold his soul for me. I left him in purgatory. I didn't shut down the gates of hell. I drove him away instead of working things out. I..._

“This isn't your fault,” says Cass. Again. Sam's lost track of how many times he's said it. He must hear it once a week.

“I'll put him to sleep,” Sam says. “I've got the blood ready. You work on resting, so you'll be ready if I can't get him down, or for the next time he goes full demon.” They both know it's no longer 'if’, but ‘when’. “Besides, I need you at full strength for afterwards anyway.”

Cass nods and once again, Sam is glad that Cass never looks at Sam with pity **.** Never treats Sam as if he's done anything shameful. As if what Sam does is a normal thing for brothers to do.

Sam goes to his room to prepare. He changes his clothes, makes confession, and tucks a syringe of consecrated blood into the pocket of his sweatpants. He stops by the kitchen to make a sandwich, although he doubts it will be eaten.

As he walks to Dean's room, he wonders if he isn't overreacting. It had been a long hunt with little sleep and it was just one comment. Maybe it was just Dean being Dean. Then he sees Dean inside his room, pacing. He's moving around restlessly as if he has an itch he just can't scratch. Sam sees an empty bottle of rum, even though he and Cass did an alcohol sweep before they left.

Cass is waiting just out of view of Dean's room. Sam nods at him in reassurance.

“I'll be in my room,” says Cass and he reaches out and gives Sam's hand a squeeze before walking past.

Sam closes the door behind him and hears Cass lock it from the outside.

Sam knows Cass will wait for his prayer, just in case. Sam has only needed him twice. Twice when they hadn't realized Dean had been killed and had gone full demon. It's harder now that he comes back within minutes of death. Sam knows black eyes are a possibility tonight. He sets the sandwich on Dean's desk and smiles. “Wanna watch something? I saw some new shows on Netflix.”

Dean scowls at him. He seems so much bigger when the Mark has control. He seems to loom over Sam despite the fact that he's shorter. He looks at Sam and Sam doesn't see much of the brother who was there yesterday.

“Sure,” he grunts but he doesn't stop pacing. Doesn't even look at the sandwich.

If Sam's lucky, Dean will settle down and binge watch a show with him until he passes out from all the drinking.

If Sam's not, Sam will handle it. He always has.

Sam edges over and turns on the TV, moving slowly and deliberately so Dean can see he isn't a threat. He sits in the chair by the bed and offers Dean the remote.

Dean selects a show without looking at the TV. He must've been suppressing the Mark longer than they'd realized, because his fingers keep stretching out into empty space; as if searching for the jawbone. Sam recognizes the signs. It won't be easy tonight.

“You almost died,” says Dean. He doesn't look at Sam. His fingers are flexing. Open and closed. Open and closed.

“I was fine,” says Sam, although he probably would've been dead if Dean hadn't had the Mark.

Dean moves, and one minute Sam is in the chair- the next he’s on his feet, pressed into the wall, Dean gripping his arms so tightly he'll have bruises the next morning.

“It's okay,” says Sam.

“I can't lose you.” There's so much grief and fear amid the anger in his eyes that it makes this easier. Sam can see Dean, the real Dean, through the Mark.

“I'm here,” says Sam. “I'm not gonna leave you.”

Dean pushes against him and kisses him hard, his mouth working possessively over Sam’s mouth and neck. He always smells like Dean - the Mark can't change that. Sam breathes in that mix of the Impala, smoke-stained flannel and denim, and the aftershave Dean's worn since he started wearing it at fifteen. If Sam closes his eyes, he can imagine he's with the real Dean, even with the hands bruising his arms.

Sam soothes him as best he can with his arms still pinned against the wall. “I'm here. I'm here.” He can't help but notice that Dean goes after him quicker each time it happens. At first, Sam gave in and went with it because it was the best way to calm Dean down and get him to sleep. Hard as it was, it's now become as normal as cleaning out and sewing up a bullet wound. He stitches Dean back together no matter how he falls apart.

Finally, Dean releases Sam's arms and Sam can move again. But Dean's already pawing at Sam's clothes. Sam has learned to wear things that can easily be pulled off. The last thing he wants is to make him angry. Dean yanks down Sam's sweatpants and rips off his t-shirt. His hands and mouth seem to be everywhere at once as he presses Sam into the wall again. He touches Sam as if he's drowning and Sam can give him oxygen.

Sam kisses him back, stroking him lovingly, trying to tell him with his body what he knows Dean can't fully hear with his words. “It's okay. I'm here.”

Dean throws him against the bed. Sam scoots more fully on it, lies on his back, and spreads his legs. Usually it takes Dean longer to get to this point.

Dean is still fully dressed as he moves on the bed, his eyes wild and hungry. Reaching between Sam's legs, he stills when he touches the plug Sam put in himself as part of his preparation. When the Mark has full control, Dean doesn't usually use lube or go slowly. Sam normally works it out before they get to this point. He didn't have the chance this time.

One second, Dean is staring at the plug, and the next Dean's hands are closing on Sam's throat. “You whore. Who’re you fucking?”

“No one else,” Sam gasps out. “I swear.”

“Don't lie to me.” Dean's eyes are fire.

“No one else.” Sam wonders if he needs to call Cass.

Just when he's about to, Dean releases Sam's neck. He tears off his shirt and strips himself of his jeans, his cock straining against his boxers. Sam has seen enough of Dean's erections to know that he probably won't get any more foreplay, so he rolls over onto his stomach and gets into a comfortable position.

Moving between Sam's legs, Dean grips the plug and rips it out. The plug is thick, and Sam's used nearly half the bottle of lube, but Dean's cock is huge and it hurts. At least he didn't tear this time. At least he's in the bunker with Dean, instead of in the cage with Lucifer.

Dean steadies his hands on Sam's shoulders, pushing him into the bed. He sets a punishing pace, pulling his cock almost all the way out before slamming it back in.

It's happened so often Sam knows how to give into it. He used to tense, making it hurt worse, but now he knows to calm and relax his body, accepting instead of fighting against the invasion. At least with Dean, he can think of childhood memories to distract himself. He sees memories of Dean taking care of him - wiping away tears, cooking mac and cheese, setting bones and saving his ass. Dean's built his life around taking care of Sam. The least Sam can do is return the favor.

The initial burning subsides, and Sam shifts his hips until Dean's hitting him just right. He doesn't like to think about how quickly he found pleasure in this. He used to think that after what Lucifer did, penetration would always be associated with pain and humiliation. He doesn't like to think about how the difference is Dean, his brother who basically raised him. He's not interested in other men. He’s only wanted to date or sleep with women since he got out of the cage, and when he watches porn, it's always straight. But he'll come from Dean's cock up his ass.

Dean is growling as he snaps his hips. The more the Mark has control, the less he speaks.

Sam strokes Dean’s fingers. “I'm not gonna leave you,” he promises. Dean has him pressed into the bed so hard he can barely breathe.

It normally calms Dean, but this time Dean bends down and bites Sam’s shoulder. Sam grins. Usually he has to work to get Dean to drink. “Harder,” he grunts and Dean obeys, sinking his teeth in until Sam can feel his skin break.

Sam doesn't know why it works. If anything should desecrate blood after a confession, fucking your brother should be towards the top of the list. For some reason though, it works. As Dean laps at the blood, his thrusts ease, no longer brutal.

“Drink,” says Sam. “Drink as much as you want.” Even though Dean isn't a demon now, it's still the best way to calm him down. Sam doesn't like to think about what that means for his brother. Or why Dean normally refuses the blood. This would all be much easier if he would just drink it on a regular basis.

Dean lifts his hands from Sam's shoulders, and snakes one arm under Sam, holding him tightly against his chest as he rolls his hips. Sam grabs his hand, his fingers threading through Dean's as he shifts his hips back to meet Dean's thrusts, his cock hard against the sheets.

“That's good,” says Sam. He knows Dean likes it when he talks, although he never quite knows what to say. “That’s good.”

“I can't lose you,” Dean says again.

It startles Sam. Dean normally never talks when he's like this. Or at least never says anything Sam would like to hear.

“I'm here. I'm not going anywhere.” Sam tries to shift away, and is surprised when Dean lets him, his cock pulling out of Sam's ass. Sam flips onto his back. Dean is looking at him with eyes more human than demon. Sam has done this often enough that he knows one more good hit of blood is all Dean needs to fully return to him.

For once, Dean isn't pushing his way in, so Sam reaches down between his legs and guides Dean's cock back inside him. He likes the feel of it spreading him, filling him, rubbing against his prostate, and making his cock spit precum on his stomach. Yet again, he wonders what the real Dean would think if he knew. Probably nothing good; so Sam never says anything, just takes the pleasure he can get in moments like this.

Sam threads his fingers through Dean's and places their clasped hands by his shoulders. He rolls his hips and that's the only encouragement Dean needs to start fucking him again. He's moving slower now. Sam prefers it hard and fast, but Dean is calmer now, and this isn't about what Sam wants, but what Dean needs.

“Yeah, Dean,” Sam moans. “Keep going.”

Dean is staring at him, and the expression on his face is almost awe. Sam’s never had to question if Dean loves him. Dean's always loved him. For Dean, it's the same as breathing. Even at Sam's worst, Dean still loved him. Sam started the apocalypse against Dean's warnings, and Dean still loved him. Maybe that's part of the problem. Sam always knew that no matter what he did, Dean would love him. He took it for granted. The sun rises, the sun sets, and Dean loves him. Loves him enough to do anything for him. Dean went to hell for him. Offering his body is the least Sam can do.

“You wanna bite me again?”

Dean frowns slightly and Sam realizes he's losing him. He quickly adds, “Harder. Fuck me harder.”

Dean obeys, snapping his hips and hitting Sam just the way he wants. Sam relishes it. He'll try again with the blood later. It's a bit of a problem - the more human Dean is, the less he wants to hurt Sam, so the harder it is to get him to drink Sam's blood.

It's almost perfect at times like these. Dean isn't fully Dean, but he's enough of him that Sam thinks this is bearable. That he could do this for the rest of his life, or until they find a cure that didn't involve the Book of the Damned.

Dean bends down for kiss, and they've done this often enough that Sam knows he's close. He eagerly kisses him back, squeezing around the cock in his ass to push him along. Dean shakes as he comes, his cock pulsing inside Sam as he empties himself.

Usually Sam finishes himself off if he doesn't come from Dean fucking him. But this time Dean slides down his body and licks at his cock.

Sam can't believe it. He freezes, watching Dean with heavy anticipation.

Dean sucks Sam's cock into his mouth. He doesn't take it all, his fingers curling around the base. It's clear from how clumsy the whole thing is that he's never done this before. It's not the best blow job Sam's ever gotten, but it's the one he most appreciates.

Sam was already close from Dean's cock. It isn't long before he tries to push Dean off, warning, “I'm gonna- I'm gonna-”

Dean plants himself firmly. Release flows through Sam, igniting him. He comes down Dean's throat with a soft cry. Feeling warm and lazy, he relaxes against the bed as he smiles at his brother.

Dean lets go of Sam's softening cock, and crawls up the bed to collapse beside Sam, burying his face in the pillow. Sam rubs Dean’s back soothingly. He’s done this often enough that he knows exactly what to do. He hums _Hey Jude_ as he gently massages the tension out of the tight muscles of Dean’s back. He waits until Dean’s breathing is even and heavy before he pulls out the syringe.

He mutters the spell Cass found, and carefully presses the needle into the patch of numb skin on Dean's buttock. It takes a few minutes for the blood to seep into Dean's blood stream, so Sam keeps humming as he massages the flesh. In fifteen minutes, he'll summon Cass.

Dean's phone rings. The noise seems like an air raid siren in the once quiet room. Sam scrambles for the phone, cursing himself for not thinking of turning it off. It's never happened before. He finds the phone and turns it off with trembling fingers. He looks back at the bed. It's too late. Dean's awake. He's staring at Sam.

Sam doesn't know if the second dose has hit or not until the blood drains from Dean's face.

“Dean,” says Sam, moving towards him.

Dean practically teleports. He's on the bed, and then he's pressed against the far wall, his face white and his eyes wide.

“Sam, I- I-” Dean says. Then he vomits.

Sam frowns. Hopefully enough blood got into Dean's system. It's impossible to get him to drink when he's this human.

Dean wipes his mouth with the back of his hand and rasps out, “I raped you.”

 _Not this time_ , thinks Sam. He doesn't say it; he knows it would only wound. He says “It's okay,” keeping his voice soft, the same as with Dean under the Mark.

“It's not! I-”

“It's okay. I chose it,” Sam assures him.

“I'm a monster.” Dean's eyes move to the weapons on the wall.

“No.” Sam moves off the bed, and reaches out for him, but Dean edges away. “It wasn't you. It was the Mark.”

Dean’s eyes are filled such horror, Sam can't help but worry that some of it is directed at him for going along with this. Sam doesn't even know how to explain it. He can't just say, “You can fuck me if you want.” Dean would probably just look at him with the same horror as is on his face now. Sam doesn't even know if that's what he really wants. It's impossible to separate his own desires from his need to give Dean anything he wants. Instead, he says, “You've sacrificed everything for me. I owe you everything. Anything. Dean, you've given me your _life_. Why wouldn't I give you my body? Why wouldn't I do everything I can to help you with this?”

Dean isn't listening. He never listens in these moments. Sam's been through enough to know. “I hurt you,” he says more to himself than Sam. “I nearly strangled you.”

“You didn't.”

“I wanted to.” Without looking at Sam, Dean grabs clothes and pulls them on.

“Wait, Dean, please.” Sam tries to move towards him but Dean flinches away. “I can fix this. You just gotta-” _Go to sleep_. He doesn't know how to say it in a way that won't make Dean suspicious. “Give me some time.”

“No. You don't know.” Dean draws a shaky breath and runs his fingers through his hair. He's talking to the door. “I- I _wanted_ to hurt you. I _liked_ biting you.”

Sam hides his smile. It's a good sign. Maybe it means this is working better than they'd realized. “The Mark wanted to - not you.”

Dean moves for the door. Sam sighs.

Dean doesn't realize the door is locked at first. He stares at it, puzzled, when it won't open. He tries again. And again. “Why is it locked, Sam?” His voice is a growl. Sam realizes Dean can't look in his eyes, or at any part of his body, really. He's talking to the wall behind Sam.

 _Because you're going to try to throw yourself in the Empty_. He doesn't say it. Doesn't want to give Dean any encouragement. It happens every time Dean remembers what he did to Sam while under the control of the Mark. “I can help you,” Sam says instead. “But you gotta let me.” He reaches out in prayer, _Cass, he woke up. I'm going to need you after all._

“God, Sam. Why the fuck are you so calm? How can you-” He presses a trembling hand against his forehead, as if the memories are physically painful.

 _-Enjoy being fucked by your brother?_ Sam doesn't know. “I told you,” he says instead. “You're my big brother. There's nothing I wouldn't do for you. _Nothing_.”

It's the wrong thing to say. Dean retches again, although this time nothing comes out.

It hurts more than Dean choking him. It hurts more than Dean raping him. Once again, he's a freak. He's impure. He's fucked in the head.

The door opens, and Cass slips inside.

Dean looks at him and then, for the first time, directly at Sam. The guilt, shame, and horror so naked on his face breaks Sam in a way Lucifer never could. Cass touches Dean's forehead and Dean collapses to the floor. Sam wants nothing more than to drink himself to sleep. But he helps Cass put Dean on the bed and watches as Cass removes Dean's memory of what just happened. Dean will never remember Sam even entering the room.

“Maybe we should consider removing the Mark,” says Cass after the spell is done. He's panting, sweat dripping off his face. The memory removal process drains him. It will take Cass days to recover. At least he has his grace back so that he _can_ recover, although each memory removal seems to take more out of him. “We can't keep doing this to him.”

He doesn't add _to us_ , even though they both know it's killing them. They both used to try to talk the other out of it, but neither would budge, both willing to give their lives for Dean.

“I know,” says Sam as he tucks Dean into bed. With Dean safely taken care of, he goes to Cass. Sam helps him to trembling feet and guides him back to his room. Cass can barely walk this time. He doesn't complain at all, but he's the most visibly damaged of the three of them.

Next time, Sam will try to handle it on his own. He grimaces at the realization that he's certain there will be another time with a wide awake Dean looking at him like- like-

He can't think about it. If he thinks about it, the darkness inside his heart will eat him alive.

As Sam settles Cass on the bed, Cass grabs his hand, his blue eyes meeting Sam's without pity or disgust- only love. “I know you want to honor Dean's request to stay away from the Book of the Damned but _Sam_ , please - he wouldn't want this for you.”

Sam's got a lump in his throat so thick he can hardly breathe or speak. “I swore I'd respect his choice on this. I don't want to use that book. I know he doesn't want us to use that book. But what am I supposed to do, Cass? Let him throw himself in the Empty? Leave him alone for eternity with all that hate and pain? I know that's what he'll want me to do,  because he'd rather get hurt than hurt me. But I can't do that to him. I _can't_. He doesn't deserve that.”

“I know,” says Cass. Cass has offered to go to the Empty himself. But since angels don't have souls, they don't know if he can. After all, why bother with the cage if Lucifer could be thrown into the Empty? There's no way they want to risk leaving Dean there alone.

Sam wants to hate Dean for being so fucking selfless. For loving Sam more than he loves himself. He wishes Dean would let him come with him to the Empty, even though he knows what it would mean for him. He wishes that he could take the Mark, make Dean forget him, and go to the Empty himself. But he can't carve out himself without carving out Dean. He takes a deep breath. “Just let me think about it.”

“It's your choice, Sam,” says Cass. “Whatever you decide.”

Once again, Sam's glad none of this fazes Cass. “If I do decide to use the book…” He hesitates. He's asking a lot and Cass has already done so much; soaked up so much pain for him, and never breathed a word to anyone about what Lucifer did to him. He trusts Cass. “Do you think you could… take my memories of Dean and me... Of everything he did when he...” He swallows and looks at Cass, afraid to ask too much. But Cass is looking at him like he knows exactly what Sam's asking and has already said yes. “If it's too much-”

“I will,” promises Cass. “I may not have the strength to remove all of these memories at once, but I'll make sure you don't remember this part of it.”

“Thank you. For everything.” Sam squeezes his hand. “Now get some sleep.”

Sam heads back to Dean's room. He turns off the TV and sets the room up as if he was never in it that night.

The next morning, Dean saunters into the kitchen, where Sam's mixing eggs. “Whatcha cooking?” Dean says as he brushes past. He's put on fresh aftershave, and Sam imagines Dean's body pressed hard against his.

“Omelettes,” says Sam, his mouth dry. “Want me to add bacon to yours?”

“Yeah, sure.” Dean opens the fridge, smells the milk, and puts it back with a disgusted look on his face. “What happened last night? I remember coming back from the hunt and going to my room, and that’s it.”

“You must've drank too much,” says Sam. He can't look at Dean without picturing Dean's mouth on his cock.

“Yeah… I don't feel hungover though.” He's rooting through the pantry. Sam knows he's looking for carbs. Dean always likes carbs in the morning, but their pantry is picked bare. They need to go to the store.

“Dean, you know I'd do anything for you, right?”

Dean's back goes stiff. He slowly turns. “Is this about the Book of the Damned? I told you to leave it alone.”

“I know, but-”

“That kinda magic always comes with a price.” He's getting visibly angry now. With the Mark, the anger is always there, simmering under the surface. “I'm not the one who's gonna pay it. You are, Sam. I'm not letting you get hurt because of me.”

 _It's too late_ , Sam thinks _. It's too late._ He says, “Yeah, I guess you're right.”

Satisfied, Dean turns back to the pantry.

“You know,” says Sam, “I think I found a case. So get this...”

**Author's Note:**

> Season 10 really bothered me, especially because I felt that there were so many things that they could've tried before going to the Book of the Damned. I wrote this in part to address those issues, so the ending of season 10 is still the same, with Castiel doing a memory wipe on both boys and them using the Book of the Damned after all.
> 
> Your comments and kudos give me life, so please let me know what you think!


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